Ground target finding mechanism for unmanned aerial vehicles to secure crop field data

Unmanned aerial vehicles (UAVs) are being used in many military and civil applications while their use along wireless sensors is emerging abruptly as it upgrades the network in terms of reliability, lifetime, and connectivity. The system performance and throughput can be further enhanced if the UAVs in use are capable to locate ground sensor nodes as a means to address them smartly. In typically localization, the direction of arrival of incoming signals from a target node is measured by using a uniformed linear array (ULA) of antennas having signal processing capabilities. However, adding numerous antennas (transmitter receivers set) on a UAV is an extra burden which ultimately effects its speed, flight time, agility, and payload capacity. Considering the issue, a typical ULA antenna system is modeled by using virtual phased array (VPA) antenna. In the proposed VPA, a single antenna installed on a moving UAV will achieve the desire results. The well-known multiple signal classification algorithm is modified to adapt this virtual antenna system. Four extra modules including calibrator, virtual antenna, rectifier, and adjustment are added in classical multiple signal classification algorithm to make it enable to work with single antenna. The proposed system mitigates the existing challenges of physical ULA and improves system throughput. Furthermore, due to its virtualness, VPA can adjust the number of antenna elements and interelement spacing, which adds multifrequency support and adaptive precision mechanism. A simulation model is developed in MATLAB to verify the performance of the VPA where the proposed system is evaluated against different scenarios with a varying number of parameters. It is found that VPA gives the same resolution and precision as a physical ULA antenna but it is more flexible, user-friendly, cost-effective, reliable, and most importantly, does not affect the UAV characteristics.